The inventive concepts generally relate to memory devices, and more particularly, the inventive concepts relate to circuits for generating a write signal, variable resistance memory devices, and methods of operating variable resistance memory devices.
Semiconductor memory devices are storage devices for storing data and for reading the stored data when necessary. Semiconductor memory devices are generally classified as either a nonvolatile memory that retains stored data in the absence of supplied power, or a volatile memory (VM) that loses stored data when power supply is interrupted. Example of nonvolatile memory include flash memory, such as NOR flash memory and a NAND flash memory. Examples of volatile memory include dynamic random access memory (DRAM) and static random access memory (SRAM).
In the meantime, variable resistance memory devices are memory devices that rely on a programmable change in resistance of a memory cell material to denote stored data. Examples of variable resistance memory devices include magnetic RAMs (MRAMs) employing tunneling magneto-resistive (TMR) films to implement variable resistance, phase change memories (PRAMs) using chalcogenide alloys to implement variable resistance, and resistive RAMs using a resistance change of a resistance change film to implement variable resistance.